Tips & Techniques

Understanding Eating for Performance for Runners

Denise Smith 
May 1, 2020

We are grateful to our friend Rachael Costello from Fox Valley Nutrition Counseling for sharing her knowledge on helping us understand the difference between calories, carbohydrates, proteins, fats!  The more a runner understands about what they are putting in the body (and when they are putting it in their body), the more they will understand how fueling can improve their performance and help with recovery.

Today  we will focus on eating for performance.  Remember, a strong nutritional foundation is the cornerstone to increased performance.  If you are regularly consuming nutrient dense foods, you will already have an edge when it comes to races.


All the cells in the body need energy to do their daily work, so without fuel, systems slow down.  Consuming enough calories (energy) everyday is the first and most important goal for all runners. The amount of calories each runner should consume is variable based on age, gender, weight, and activity level.  This can be determined with help from a registered dietitian.


Carbohydrates are the preferred source of energy for the cells.  It is the most efficient source of energy.  Your body has the capacity to store carbohydrates to some extent, and will draw on these stores when exercising.  Again, the amount of carbohydrates you will need to consume depends on several factors. Length of time spent running and level of intensity will influence your actual needs. Good carbohydrate choices include whole grains, vegetables, and fruits.  Try to avoid overly processed foods and added sugars.  These foods may provide carbohydrates but lack the numerous benefits our plant sources contain like vitamins, minerals, and fiber.


Protein is not a primary fuel source but it is important for muscle recovery.  There is often a focus on protein in athletes.  Our bodies cannot store protein.  This means that if you over consume protein, your body will get rid of it. As an example, a non-runner needs 0.8g/protein/kg body weight. In a 150 pound person, this would be about 54g or protein per day which can be met by eating a 5oz chicken breast and 2 eggs.  An endurance runner may need 1.2-1.5g of protein per kg of bodyweight.  So that same 150 pound person, as an endurance runner, will need 82-102g of protein. Increasing your chicken to 9oz and having the same 2 eggs will get you to that range. So consuming protein powders or excessive amounts of protein is really unnecessary. When runners are consuming enough calories, they are generally consuming enough protein overall. (This is also true of the general population.)


Fat recommendations are not different for runners than for the general population and should comprise 20-35% of daily calories.  A low-fat ( less than 20%) diet is not recommended.  Fat from unsaturated sources is better for overall health.  Foods like avocados, salmon, walnuts, chia seeds, and olive oil are all good sources of fat.

Other nutrients that may play a role in performance:

  • Iron: If a runner is not meeting iron needs, anemia may result. A primary symptom of anemia is fatigue which can obviously hinder performance.  It is recommended that iron comes from the diet and not from a supplement.  This is because iron can become toxic at high levels, which happens much more readily with supplements. Some runners will require a supplement, however this should be done only after having bloodwork to determine current levels, and under physician guidance.
  • Sodium: With increasing perspiration, sodium can be lost. This can lead to electrolyte imbalance in the body. Warm weather and longer runs can lead to sodium deficiency.  Ways to avoid this include not overhydrating, and consuming adequate sodium in the diet.  After long runs or on very hot and humid days, you may need to consume sodium during and/or after your run.

In summary, runners should first be concerned with consuming adequate calories.  The greatest amount of calories (45-65%) should come from quality sources of carbohydrates like whole grains, vegetables, and fruits.  Protein is most important for recovery and runners who are consuming adequate calories generally consume adequate protein.  Fat should make up 20-35% of calories and should come from unsaturated food sources.

Every person and every athlete is different.  These are general recommendations and may not apply to you personally.  If you have any questions, please consult with a registered dietitian, who can individualize your needs.

-Rachael Costello MS, RDN, LDN, is a registered dietitian nutritionist, and practices in Algonquin, IL.  For more information, visit

Meet the Author
Denise Smith graduated from Marquette University in 2002 with a Master’s Degree in Physical Therapy and has been a certified running technique specialist since 2014. She is a consultant for multiple local middle and high schools and instructs courses in Kinesiology at McHenry County College. Denise also travels the country as part of the Pose Method education team with a lecture series on injury prevention and treatment along with the running technique certification course.
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